For elements such as resistors, ceramic condensers, thermistors, varistors, plasma display panels, and the like, electrodes are generally formed of compositions comprising silver powder as a conductive filler using a firing process after patterning via screen printing, off-set printing, photolithography or the like.
However, using silver powder as the conductive filler in the formation of the composition for electrodes can increase manufacturing costs. Using silver as the conductive filler can also cause electrical shorts between adjacent electrodes in an electrode pattern formed of the silver powder due to migration of silver components caused by movement of electrons. This, in turn, can deteriorate the reliability of the electrodes.
To solve these problems, there have been attempts to develop cheaper conductive filler materials that can replace silver powder.
One conductive filler material employs aluminum as the conductive filler. Aluminum, however, is oxidized during the firing process in air, causing a rapid decrease in electrical conductivity of electrodes made from a composition which contains aluminum filler.
Further, because the firing process is generally repeated in the formation of the electrodes using the composition, the use of aluminum as the conductive filler results in a rapid decrease of electrical conductivity since the degree of oxidation of aluminum increases with each firing process.
To solve these problems relating to the use of aluminum as the conductive filler, the use of a spherical powder comprising aluminum or aluminum alloys has been proposed. However, the use of the spherical powder results in a high resistance of an electrode several thousand times that of the electrode formed using the silver powder and causes an increase of 10% or more in resistance of the electrode in each firing process. Thus, the spherical powder comprising aluminum or aluminum alloys have not been practical for producing electrodes.